In a cutting machine such as a band saw machine, a three-vise type workpiece feed/clamp apparatus is developed instead of a two-vise type workpiece feed/clamp apparatus (see a Patent Document 1 listed below or others). According to a three-vise type workpiece feed/clamp apparatus, it becomes possible to improve productivity by shortening a residual material and by shortening an operation cycle time. A two-vise type workpiece feed/clamp apparatus includes a feed vise mechanism and a main vise mechanism. The feed vise mechanism is provided movably in a feed direction on an upstream side of a cutting position (on an upstream side in the feed direction). The main vise mechanism is provided just on a downstream side of the cutting position (just on a downstream side in the feed direction), or provided dividedly just on an upstream side and just on a downstream side of the cutting position (divided-vise type).
A prior-art three-vise type workpiece feed/clamp apparatus includes a feed vise mechanism movably provided in a feed direction on an upstream side of a cutting position. The feed vise mechanism has a pair of feed vise jaws for clamping a workpiece. The pair of vise jaws are facing to each other in a width direction perpendicular to the feed direction. In addition, the feed mechanism has a feed vise moving cylinder for moving a first feed vise jaw (one of the feed vise jaws) in the width direction and a feed vise shifting cylinder for shifting (hereinafter, the term “shift” will be used to mean “slightly move”) a second feed vise jaw (the other of the feed vise jaws) in the width direction. Here, when (a piston of) the feed vise shifting cylinder reaches its stroke end on one side of the width direction, a vise surface of the second feed vise jaw reaches a vise reference position in the width direction.
A prior-art three-vise type workpiece feed/clamp apparatus also includes, in addition to the above-explained feed vise mechanism, an upstream main vise mechanism just on an upstream side of the cutting position (just on an upstream side in the feed direction). The upstream main vise mechanism has a pair of upstream main vise jaws for clamping a workpiece. The pair of upstream main vise are facing to each other in the width direction. In addition, the upstream main vise jaw mechanism has an upstream main moving cylinder for moving a first upstream main vise jaw (one of the upstream main vise jaws) in the width direction and an upstream main shifting cylinder for shifting a second upstream main vise jaw (the other of the upstream main vise jaws) in the width direction. Here, when (a piston of) the upstream main shifting cylinder reaches its stroke end on the one side of the width direction, a vise surface of the second upstream main vise jaw reaches the above-explained vise reference position in the width direction.
The prior-art three-vise type workpiece feed/clamp apparatus includes, in addition to the feed vise mechanism and the upstream main vise mechanism that are explained above, a downstream main vise mechanism just on a downstream side of the cutting position (just on a downstream side in the feed direction). The downstream main vise mechanism has a pair of downstream main vise jaws for clamping a product correspondent portion of the workpiece (a portion that will be a product by being cut out from the workpiece). The pair of downstream main vise are facing to each other in the width direction. In addition, the downstream main vise jaw mechanism has a downstream main moving cylinder for moving a first downstream main vise jaw (one of the downstream main vise jaws) in the width direction and a downstream main shifting cylinder for shifting a second downstream main vise jaw (the other of the downstream main vise jaws) in the width direction. Further, when (a piston of) the downstream main shifting cylinder reaches its stroke end on the one side of the width direction, a vise surface of the second downstream main vise jaw reaches the above-explained vise reference position in the width direction. Here, a thrust force of the downstream main shifting cylinder (a force for pressing the second downstream main vise jaw) toward the one side in the width direction is set larger than a thrust force of the downstream main shifting cylinder (a force for pressing the first downstream main vise jaw) toward the other side in the width direction. As the result, when the product correspondent portion of the workpiece is clamped by the pair of the downstream main vise jaws, the vice surface of the second downstream main vise jaw is located at the vise reference position.